Question

when in earths history did oxygen peak and carbon dioxide and temperature both fall all at the same time
600 mya
500 mya
400 mya
300 mya
200 mya
100 mya

Explanation:

To determine when oxygen peaked and carbon dioxide and temperature fell simultaneously, we refer to Earth's geological and atmospheric history. Around 300 million years ago (MYA), during the Carboniferous period, there was a peak in oxygen levels due to extensive plant growth (which also led to coal formation), along with drops in carbon dioxide and global temperature.

Answer:

300 MYA (the option with "300 MYA")